The invention relates to skis.
The use of a single reinforcing glass fiber/resin casing completely enclosing a single-piece light core is known, such a casing extending substantially to the edges of the ski which are fitted with hard protective plates. Such skis are still found to be satisfactory for all-round skiing, but are not suitable for high speed downhill or slalom competitive skiing.
To improve performance, several elongated core elememts of light material, placed side-by-side within the ski and extending along the ski, were each encased in a fiber-glass fabric impregnated with a resin which upon polymerisation solidified and bonded the core elements together and to the surrounding outer case of the ski. The provision of several such encased core elements enabled a notable amelioration of performance, by providing a light ski resistant to torsion while allowing a modulated flexibility along the length of the ski. However, the manufacturing process is clumsy, and the joints between each adjacent fiber/resin case are subject to high stresses, particularly torsional, and are liable to crack and allow penetration of humidity which reduces the useful life of the ski.
A more recent proposal has been the use of a generally .OMEGA.-shaped fiber/resin reinforcement embracing but not encasing the central part of a split core. This enables manufacture to be simplified and the risk of cracks to be reduced.
All of these known skis however have a high resistance to lateral flexibility whereby during skiing, especially at high speeds, adaptation of the ski to irregularities of the slope is limited.